It is known to prepare polymers from certain cyclobutanediols and aromatic dihydroxy compounds such as 2,2-bis(4-hydroxyphenyl)propane, commonly referred as bisphenol-A (BPA). The polymers prepared therefrom employ solvents and high temperatures. U.S. Pat. Nos. 3,326,855; 3,313,777; 3,546,331; 3,546,332; 3,541,200; 3,375,210 and 3,674,623 disclose polymers prepared from tertrahalobutanediol and particularly tetramethylcyclobutanediol (TMCBD). As disclosed therein, TMCBD, for example, can be reacted with other reactants such as aryl dihydroxy compounds usually at elevated temperatures and in the presence of organic solvents. Several of the references are also directed to methods of surface crystallization of copolymers prepared from TMCBD and dihydroxy co-reactants. The reactions disclosed therein do not employ aliphatic haloformates, which in the instant invention are prepared prior to the reaction thereof with an aryl dihydroxy reactant. Otherwise, if an aromatic haloformate is produced instead of forming an aliphatic haloformate, the reaction with an aliphatic diol will not produce a polymer of alternating aliphatic and aromatic species.